Interpretive Summary: Roofed and confined cattle feeding facilities are increasingly popular in the Northern Great Plains. Producers who use confined feeding facilities such as the monoslope barn, typically add bedding once or twice per week. Some producers allow a mound of bedding and manure to accumulate in the center of the pen and remove manure only from the area surrounding this mound. The mound of bedding is referred to as a bedded pack. The length of time that producers allow the bedded pack to remain in the facility varies from one week to longer than a year. A variety of bedding materials are used in these barns, with crop residues such as corn stover and soybean stover being two popular bedding materials. However, little is known about the affect of bedding material and age of the bedded pack on air quality in the cattle barns. The objective of this study was determine the effect of bedding material (corn stover vs. soybean stover), age of the bedded pack (0 to 3 weeks vs. 3 to 6 weeks vs. 6 to 9 weeks), and temperature (hot vs. cold) on air quality in the barn and the nutrient value of the manure that is removed from these barns. Lab-scaled bedded packs were used for this study. Air quality gases (ammonia, methane, carbon dioxide, and nitrous oxide) were measured. Results of this study indicate that concentration of all gases except nitrous oxide are approximately twice as high during a hot season compared to a cold season. Carbon dioxide and methane increased as the bedded packs aged, indicating that maintaining a bedded pack at least 9 weeks will increase the concentration of these gases.

Technical Abstract:
Bedding material is used in livestock operations to facilitate manure management and provide comfort for the animal. However, the implications of bedding on fertilizer value and gaseous emissions are not fully understood. The objective of this study was to determine differences in ammonia (NH3), carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4) concentrations from bedded beef cattle manure related to age of the manure bedded pack (0 to 3, 3 to 6 and 6 to 9 weeks), bedding material (corn stover (CS) or soybean stubble (SB)), and temperature (10°C or 40°C). Twenty four lab-scale manure packs were monitored in temperature and humidity-controlled chambers (n=2 per treatment). Freshly collected fecal material from an open feedlot, urine, and bedding were added weekly to the bedded packs. Flux chamber measurements from the pack headspace were analyzed for CO2, N2O, and CH4 after 0, 24, 46 and 144 h and for NH3 at 0, 5, 9, 23, 34, 46 and 144 h after material addition. The study showed that the higher storage temperature of 40°C significantly increased all gas concentrations approximately twofold, compared to cooler storage at 10°C. The CO2 and CH4 concentrations significantly increased as the age of the bedded pack increased. There were periodic differences in NH3 and N2O concentrations over time with different materials.